Generally, digital cameras are image recording media capable of photographing a plurality of still images without using film. Such a digital camera typically uses an image pickup device, which is a kind of semiconductor device, such as a charge coupled device (CCD) or complementary metal oxide semiconductor (CMOS). In the digital camera, an object image formed on the image pickup device through a lens is converted into an electrical signal by the image pickup device, and the electrical signal is stored as a digital signal in a mobile phone or PDA in which the digital camera is mounted. In order to protect the image pickup device from contamination or pollution (i.e. from dust or water vapor), the image pickup device is generally sealed in a structural package.
A typical image sensor chip package 100 is illustrated in FIG. 1. The image sensor chip package 100 is constructed to include a base 10, a chip 12, a plurality of wires 13, an adhesive glue 14 and a cover 15. The base 10 includes a board portion 101, a frame portion 102 upwardly extending from a periphery of the board portion 101, and a cavity 103 cooperatively formed by the board portion 101 and the frame portion 102. A plurality of top contacts 104 and bottom contacts 105 are respectively mounted on two sides of the board portion 101, and the top contacts 104 are contained in the cavity 103. A plurality of conductive interconnecting portions 106 are arranged inside the board portion 101 so as to electrically connect the top and bottom contacts 104, 105. The chip 12 includes an active area 121 and a number of pads 122 formed thereon. The chip 152 is received in the cavity 103 and adhered to the board portion 101 of the base 10. The wires 13 are provided to electrically connect the pads 122 of the chip 12 and the top contacts 104 of the base 10. The cover 15 is transparent and secured to the top of the frame portion 102 via the adhesive glue 14, thereby hermetically sealing the cavity 103 and allowing light beams to pass therethrough.
In the foresaid package 100, the base 10 is essentially made from ceramic, which is expensive and accordingly results in increased cost of the package 100. During the process of forming the contacts 104, 105 and the interconnecting portions 106 on the base 10, firstly a number of interconnection holes are punched in the base 10, secondly, the base 10 is copper plated, via electroless or electrolytic deposition onto the surface of the base 10 and onto the surfaces created by the interconnecting holes. Finally, the contacts 104, 105 are formed by means of etching. Accordingly, the contacts 104, 105 and the interconnecting portions 106 are electrically connected with each other. It is obvious that this method of forming the contacts 104, 105 and the interconnecting portions 106 is complex and as a result it is expensive. Furthermore, water vapor can enter the cavity 103 via the interconnection portions 106. Thus, the chip 12 may become polluted, and even be damaged.
Additionally, the cavity 103 of the base 10 must contain both of the top contacts 104 and the chip 12 therein, and there must be a space between an outer periphery of the chip 12 and an inner periphery of the frame portion 102 of the base 10 for allowing movement of a wire bonding tool, which accordingly results in a relatively large sized package 100 relative to the volume of the chip 12.
Furthermore, the relatively large volume of the package 100 results in more dust-particles adhering to the cover 15, the board portion 101 and the frame portion 102 of the base 10. Thus, more dust-particles will drop onto the chip 12. The dust-particles obscure the optical path and produce errors in the image sensing process. Accordingly, the quality and/or reliability of the package 100 may be adversely affected.
Therefore, a digital camera module with an improved image sensor chip package is desired in order to overcome the above-described shortcomings.